50 



Wm. H. Koane's, lower stratum, Silica and alumina, &c. 50 



Carb. lime, 4 



Greensand, 46 



Gypsum, 3 



Tarby, lower stratum, Silica, alumina, Lc. 40 



Carb. lime, 3 



Greensand 57 



Do. upper stratum, Gypseous earth containing 



from 6 to 10 per cent, of 

 gypsum, and from 10 to 15 

 per cent, of grecnsand. 



Berkeley, Silica and alumina, he, 50 



Greensand, 50 



Viewing these results generally, it is apparent, that while in some 

 cases the efficacy of the marl would be ascribable in a degree to the 

 calcareous carbonate or sulphate present In large proportion, in a 

 great many others the greensand ought to be regarded as the chief, 

 if not the only agent in the ell'ects. A dressing of many of these 

 marls to the extent usual in the application of the Miocene shell 

 marl would scatter upon the soil a proportion of grecnsand, nearly 

 as great as the average quota which is at present in use in New 

 Jersey, and in the richer sorts, a much less proportion would be 

 necessary than it is customary to apply where the shells abound. 



We are struck, in considering the composition of these marls, with 

 the happy variety of constitution which they exhibit, which, should 

 there be any specific action of the respective ingredients on particu- 

 lar vegetables, which there is reason to believe is the case with one 

 (the gypsum,) will the more completely adapt them to the variety of 

 crops to which the farmer would wish them to be applied. 



Some caution will be necessary in distinguishing the marls, con- 

 taining a large proportion of greensand, from dark greenish clays and 

 sands, which have sometimes been mistaken for them. These clays 

 are always entirely destitute of fossils ; they have an astringent or 

 copperas flavour, and generally a strong sulphureous odour, though 

 a slight smell of this kind is also often observed in the best marls. 

 The occurrence of small shells sparsely distributed and in a decom- 

 posing state is very frequent in the good marls, though, an almost 

 total absence of shells is sometimes observed. Fine sparkling scales 

 of Mica, (not gypsum, as supposed by some,) are generally present 

 in considerable proportion, and have led those who speculated upon 



